Lock with a separate bottom plate



March 10, 1970 A. K. NIIILOLA ET AL 3,499,301

LOCK WITH A SEPARATE BOTTOM PLATE Filed Aug. 10, 1967 2 Sheets-Sheet 1 March 10, 1970 A. K. NIILOLA ETAL 3,499,301

LOCK WITH A SEPARATE BOTTOM PLATE Filed Aug. 10, 1967 2 Sheets-Sheet 2 FIG.5

United States Patent U.S. Cl. 70-52 9 Claims ABSTRACT OF THE DISCLOSURE A key operated lock with locking means of the cylinder lock type. The locking means are protected by a separate disk of hard material which is permanently fixed to the bottom of the lock by means of plastic deformation of an attachment part.

The present invention relates to a lock consisting of a hollow casing with a bottom plate at one end.

In the lock casing there is an opening through which the lock mechanism is inserted. This opening is normally more or less effectively protected by the way the lock is used. For instance in doorlocks the said opening is inside the door, and in padlocks it is directed against the shackle, so that it is protected by the shackle and by the attachment plates which carry the lock. This type of lock casing can be made by casting or by machining from solidbars. This makes the manufacturing costs rather high. Cast lock casings cannot be hardened and so also have the considerable drawback that they can be destroyed rela tively easily by means of drilling or sawing.

The object of the present invention is to provide a reliable and simple attachment of a front-plate into the bottom part of the lock casing. By this means a simpler manufacture is obtained and it is at the same time possible to obtain increased security by making the frontplate of hard material. The invention is characterized by the fact that the bottom of the lock casing comprises a separate front plate which, by means of plastic deformation of an attachment part in the bottom of the lock casing or by means of one or several attachment members, is attached to the lock casing. This type of attachment gives a reliable joint because it is easy to apply high attachment forces during the manufacture of the lock, but it is diflicult to apply a separating force to the frontplate when the lock is in use. It should be noted that the attachment of the front-plate can easily be made such that the front-plate cannot be grabbed with any tool.

The invention also has the advantage that the manufacture of the lock casing is simpler when the front-plate is a separate part. The main part of the lock casing can then be made of a profile-tube and, in that case, the necessary machining of the' casing is substantially reduced. It is also possible to make the front-plate of hard material, which with some types of lock, for instance built-in doorlocks, is sufiicient to protect the entire lock, because the front-plate is the only visible part of the lock.

The attachment part, which is subjected to plastic deformation, may be an annulus of soft material which is forced in between the front-plate and the surrounding part of the bottom lock casing. The space between the two abovementioned parts is preferably given a conical shape. The attachment pait may alternatively be a part of the lock casing or of the front-plate. Preferably the attachment part is a part of the lock casing. This is necessary if the front-plate is made of hard material. The attachment part is pressed into an attachment recess in the corresponding part of the lock. The attachment recess is ice usually oblique, ie a conical groove or a groove with an enlarged bottom part. The attachment part can then be fixed merely by pressing the lock casing against the attachment recess, so that the material of the former part flows into the recess. Preferably a special attachment projection is made for instance in the form of an annular projection which during deformation is forced sideways into the attachment recess.

Especially in padlocks, it is not usually sufficient that the lock mechanism is protected by a hard front-plate. In order-to prevent destruction of the lock by sawing across the lock casing or by removing the front-plate upon destroying the lock casing around the front-plate. A number of pins can be provided around the front-plate. These pins have an extension substantially at right angles to the front-plate. Preferably they are provided with heads or corresponding parts, which partly overlap the frontplateon its outside. The pins should of course extend far enough into the lock casing to protect all the essential parts of the lock. In the following the invention will be described more fuly with reference to the accompanying figures, which schematically show different features of the invention.

FIGURE 1 shows a section of the padlock according to the invention. FIGURE 2 is a view of the padlock of FIGURE 1 as seen from the keyhole end.

FIGURE 3 shows the section III-III of FIGURE 2.

FIGURE 4 shows an attachment part in the form of an annulus.

FIGURES 5 to 7 show sections of three different ways in which the front-plate may be attached to the lock casing, by means of an annular attachment part being integral with the lock casing.

In the figures, 1 indicates the main part of the lock casing, 2 the front-plate and 3 the keyhole in the middle of the front-plate.

The padlock shown in FIGURE 1 also comprises shackle 4 of hardened material and a cylinder lock 5 inserted in a boring 6.

At the opening of the boring 6 in the bottom of the lock casing 1 there is a conical recess 7 which encloses the front-plate 2 and a plastically deformed attachment ring 8 which has been forced in between the front-plate 2 and the conical wall of the recess 7. The front-plate 2 has the formof a truncated cone and its greatest diameter is slightly smaller than the smallest diameter of the conicalrecess 7, so that the front-plate can be inserted into the recess. Before the assembly of the attachment ring 8, it can be cylindrical as shown in FIGURE 4. When the attachment ring is forced into its proper place, it becomes conical and fills the free space around the frontplate 2, thereby firmly securing the front-plate.

The padlock shown has also been provided with four pins 9 of hardened steel which, from the bottom side of the lock casing have been forced into corresponding borings in the lock 5 substantially parallel to the cylinder.

The pins 9 are long enough to reach past the end of the shorter leg of the shackle 4, when the shackle is in its locking position. At the same time, the pins 9 cover the main part of the cylinder lock 5. As shown in FIG- URES 2 and 3 the pins 9 are arranged very close to the front-plate 2 and provided with heads 9' which overlap the front-plate 2.

In the padlock described, the front-plate 2 protects against breaking into the lock by means of drilling and the pins 9 protect against sawing across the lower part of the lock casing. The shackle protects against sawing across the upper part of the lock casing.

The front-plate 2 can alternatively be attached to the lock casing merely by the pins 9 being an interference lit in their borings. In order to obtain a more reliable ioint, the pins may be provided with suitable protrusions which would cut into the surrounding material. It is also possible to replace the pins 9 by screws of substantially the same shape. The heads of the screws are preferably designed to break under the assembling torque, exactly at the level of the bottom face of the lock casing. By this means a suitable attachment pressure is automatically obtained, and at the same time the advantage is obtained that the screws cannot be unscrewed.

FIGURES 5 to 7 show another way of joining the frontplate and the lock casing. This way is especially intended for built-in cylinder locks, but it can also be used on padlocks and other types of lock. In the FIGURES 5 to 7 the lock casing 1 is provided with an annular protrusion 15 which, during deformation sideways is forced into an attachment recess 14 in the front-plate.

In the FIGURES 5 and 6 the attachment recess 14 is conical, i.e. it runs obliquely outwards or inwards. The protrusion 15, which is cylindrical at the beginning, is subject to deformation when it is forced into the attachment recess. By this means the front-plate is effectively fixed to the lock casing 1. In FIGURE 7, the attachment recess 14 is enlarged at its bottom end and this enlargement is filled more or less completely by the protrusion 15. The method described to attach a front-plate can also be used to provide ready-made locks with a protective plate. A suitable recess is made in the bottom of the lock. In this recess there should be a suitable attachment protrusion, preferably of annular shape. As described above a front-plate having a corresponding attachment recess can then be pressed onto the lock casing.

The invention is not limited to the embodiment shown.

We claim:

1. A key operated lock comprising a hollow lock casing enclosing locking means of the cylinder lock type, said lock having a bottom portion including a key hole for said key, said bottom comprising a separate protecting disk of hard material of substantially the same diameter as said locking means and covering said locking means, said disk being attached to said lock casing by means of plastic deformationof an attachment part, said attachment part comprising an annular member of soft material, said member being forced between said protecting disk and a part of said lock casing surrounding said disk.

2. A lock according to claim 1, wherein said lock is a padlock having a number of pins of hard material arranged around said protecting disk substantially at right angles to said disk and arranged so as to protect against sawing across the casing of said padlock.

3. A lock according to claim 2, wherein said pins are positioned adjacent to said protecting disk so as to prevent removal of the disk 'by the destruction of the lock casing around said disk.

4. A lock according to claim 2, wherein said pins are provided with a head, said head partly overlapping said protecting disk.

5. A lock according to claim 2, wherein said pins extend substantially parallel to said locking means along their main part.

6. A key operated lock comprising a hollow lock casing enclosing locking means of the cylinder lock type, said lock having a bottom portion including a key hole for said key, said bottom comprising a separate protecting disk of hard material covering said locking means, said disk being attached to said lock casing by means of plastic deformation of an attachment part, said attachment part being integral with said lock casing and having a force fit in an attachment recess extending into said protecting disk from an opening on the surface of said disk facing said locking means, the attachment part undergoing plastic deformation while being so forced.

7. A lock according to claim 6, wherein said attachment recess is inclined so as to cause bending deformation of said attachment part.

8. A lock according to claim 6, wherein said lock casing forms the casing of a cylinder lock and said protecting disk forms the bottom portion of said cylinder lock.

9. A lock according to claim 6, said attachment recess having an enlarged bottom part.

References Cited UNITED STATES PATENTS 212,892 3/1879 Budd 52 327,715 10/1885 Paull 70-39 X 465,897 12/1891 Troast 7'0 52 1,348,234 8/1920 Much 7O--38 X 2,281,088 4/1942 Nelson 70-38 FOREIGN PATENTS 632,768 12/ 194-9 Great Britain.

MARVIN A. CHAMPION, Primary Examiner E. I. MCCARTHY, Assistant Examiner 

